Physical Science 1

Chapter 16 Sec 1 Matter & Temperature

KINETIC THEORY OF MATTER--Matter is made up of tiny particles in constant motion

* heat them and their speed increases

* tiny particles collide with each other & the walls of their containers

• 4 DIFFERENT STATES OF MATTER

• Solids: definite shape and volume

* arranged in repeating geometric patterns called crystals

* those that aren’t made of crystals are called “amorphous” solids= having no form

* ex. Glass, wax, plastics---some scientists classify them as very thick liquids

States of Matter, cont.

LIQUIDS—definite volume, but takes the shape of container

Particles have enough KE for them to move over and around each other—lets liquids flow

Are NOT compressible– 1 liter cannot be pushed down into smaller container

GASES---no definite shape or volume

Expands or contracts to fill available space

Spreads evenly in all directions Compressible

States of Matter, cont.

PLASMA—most common state of matter in the universe

Gas-like mixture of positively & negatively charged particles

Matter heated to very high temps.---violent collisions

Our sun is plasma, but closer to home what is an example????????

Thermal Expansion-matter expands as it gets hotter & contracts as it cools (except for one very common substance—name it!)

Heat of Fusion- E required to change gas to a liquid

Heat of Vaporization- E required to change liquid to a gas

Water Cycle Earth’s water is 3% fresh,

97% _______ Of the 3% fresh, 2/3 is

locked up in glaciers, deep aquifers & ice (= 2%)

That leaves 1% of Earth’s water for freshwater needs of humans, animals & plants

Human usage: 54% industry, 35% farming, 11% home use

List all the times you have used water today…….

Water cycle, cont. Water molecules stay in the

atmosphere ~ 10 days before condensing & falling as precipitation

Water in lakes remain up to 10 years

In glaciers & deep aquifers, molecules remain for CENTURIES!!!

60-80% of precip that falls returns directly to the atmosphere by evaporation

Evap from plants: transpiration—from holes (stomata) on the underside of leaves

20-40% of precip is run-off or groundwater

Water Cycle Evaporated water (water

vapor) rises, cools & condenses, forming clouds

Vapor condenses around a

condensation nuclei: smoke, pollution, salt

Forms into clouds, 4 types:

CUMULUS—white fluffy clouds that you see on a nice, sunny day

CIRRUS—thin, wispy clouds above 7 km made of ice crystals

NIMBUS—gray clouds that bring rain & snow

STRATUS—thick blanket-like clouds below 2 km

Precipitation

As water vapor droplets collide they become raindrops and when they become heavy enough fall to Earth as:

Rain—liquid droplets

Drizzle—fine liquid mist

Sleet—frozen and liquid drops mixed—freezes on contact

Snow—frozen flakes

Hail—frozen spheres—can get very large

Water Cycle, cont. During recent ice age in

Northern Hemisphere (10,000-15,000yrs ago), water formed into huge glaciers

Very little water returned to atmosphere by sublimation—ice directly to water vapor

Sea level dropped more than 100m (= _______ ft ?)

Precipitation = evaporation; no NEW water is ever introduced into the cycle

SOOOOO, the water you brushed your teeth with this morning could have been used by the dinosaurs

Water Pollution

The addition of foreign materials, compounds, chemicals into our water that reduces its purity

5 types:

Raw sewage: human/animal, depletes oxygen and bacteria cause diseases (typhoid, cholera, hepatitis, E. coli infections, Giardia)

Toxic wastes: manufacturing processes, contaminates groundwater/wells

Fertilizers: algal blooms

Pesticides: stays in fat cells of animals thru-out food chain

Thermal: addition of heated water (power plants)

16-3 Behavior of Gases Pressure: the amount of force

exerted per unit of area

(P= F/ A) Depends on how often the tiny

particles hit container walls

Pascal: the SI unit of pressure (Pa); very small, so most pressures

are stated in KPa (1000 Pa) 1 pascal of pressure = 1 Newton per

sq meter (1Pa = 1 N/ m2) Newton is about the wt of a stick of

butter

At sea level, atmospheric pressure = 101.3 KPa or 101,300 Newtons/sq. meter

Gas Laws Boyle’s Law (Robert 1627-1691, British) if you decrease the volume of a container of gas, the pressure of the gas will increase (provided the temp doesn’t change)

Decrease pressure—volume increases

This is an inverse relationship

Gas laws,cont. Charles’s Law (Jacques

1746-1823, French) volume of gas increases with increasing temp (provided

pressure doesn’t change) Kinetic Theory explains—

heated particles strike walls of container more which increases volume of hot air balloon

This is a direct relationship Empty aerosol cans—put it in

a fire and the remaining particles expand and they can’t increase the volume of the can without the can exploding!!

Absolute Zero Temperature at which all particle motion

would cease Charles found this to be – 2730 C This would be equal to 0 Kelvin In Kelvin there are no negative

numbers---all positive We also do not use a degree symbol with

Kelvin Add 273 to the Celsius reading to get the

Kelvin reading Subtract 273 from the Kelvin reading to get

Celsius

-1050 C = ?K 00 C =?K 700 C = ?K 1000 C =?K 273 K = ?°C 0 K = ?°C 100 K = ?°C 500 K =?°C

Uses of Fluids Archimedes’ Principle- buoyant force on an object in a fluid = weight of the fluid displaced by the object

Buoyant Force- the upward force exerted on an object when it is completely immersed in a fluid; determines whether an object will float or sink in a fluid

Buoyant force < object’s wt =sinks Buoyant force =object’s wt =floats Buoyant force >object’s wt=object

moves upward Floaters/ Sinkers Demo—

decide if the object will float or sink in water

Uses of Fluids, cont. Pascal’s Principle–

pressure applied to a fluid is transmitted unchanged throughout the fluid; hydraulic lifts use this principle

Bernoulli’s Principle— as the velocity of a fluid increases the pressure exerted by the fluid decreases

For example—air speeds over the wing of a plane increase and this decreases the downward air pressure so the higher air pressure under the wing results in a net upward force on the wing, causing lift

Venturi Effect— air flows faster when forced to flow through narrow spaces and as a result the pressure of the fluid drops

This can be a problem in big cities with tall skyscrapers that are close together---the drop in air pressure can cause windows to POP OUT!!

Homework Place a small amount of air

in a re-sealable plastic bag Put bag in the freezer

overnight (describe) Remove bag in the

morning or a few hours later (describe)

Heat the sealed bag with a hairdryer (describe)

What happened? Which law did you just

prove? Attach the bag to your

answers and bag descriptions